The present invention relates to the anionic polymerization of generally olefinic-type polymers and the termination thereof with an amine end group. More specifically, the present invention relates to the formation of amine terminated, anionically polymerizable polymers which are stable and yet can be reacted with amine reactive compounds such as monomers or polymers to form block copolymers. Such block copolymers are generally easily processed in a manner typical of the anionically produced polymers such as elastomers but yet, upon cure, generally exhibit properties typical of the other constituent. A specific aspect of the present invention therefore relates to the formation of an epoxy block copolymer. In another specific aspect, the present invention relates to the formation of a urea-formaldehyde graft copolymer. In yet another specific aspect, the present invention relates to the formation of an acetalized polyvinyl alcohol graft copolymer. In yet another specific aspect, the present invention relates to the formation of a phenol-formaldehyde graft copolymer. In yet another specific aspect, the present invention relates to the formation of a nylon block copolymer. In yet another specific aspect, the present invention relates to the formation of a urea block copolymer. In yet another specific aspect, the present invention relates to the formation of a urethane-urea block copolymer. In yet another specific aspect, the present invention relates to the formation of a urethane block copolymer. In yet another specific aspect, the present invention relates to the formation of an imide block copolymer.
The polymerization of conjugated dienes and/or vinyl substituted aromatic compounds with organo alkali metal initiators is well known in the art. The resulting alkali metal terminated polymers are often reacted with polyfunctional compounds to couple the polymers, for example, U.S. Pat. Nos. 3,135,716; 3,468,972; 3,225,119 and 3,281,383. However, none of these patents disclose the preparation of anionically polymerized polymers which contain a terminal amine. Moreover, anionic polymers used in the preparation of block copolymers having a constituent other than the initial constituent is not disclosed.
Various inventions exist which utilize amines for various purposes. For example, U.S. Pat. No. 3,017,392 relates to the formation of linear polyamides by the polymerization of lactams. The polymerization is carried out in the presence of a tertiary-nitrogen atom-containing compound and a molecular weight-regulating concentration of a primary or secondary amine. In U.S. Pat. No. 3,028,369, a polymerization of lactams is enhanced by the addition of an organic isocyanate used as an initiator or promoter. In an article by Mottus, Hendrick and Butler, Polymer Preprints, 9(1), 390(1968), it is stated that the initial polymerization of caprolactam can be controlled with use of amine modifiers to give products over a wide range of molecular weights. Primary amines are effective as modifiers with secondary amines showing less modifying action and tertiary amines being inactive. The control is hypothesized to involve chain termination and acyl transfer. However, none of these patents suggests the amine termination of an anionically polymerized polymer which may be utilized in the formation of block copolymers.
In U.S. Ser. No. 219,161, now U.S. Pat. No. 3,838,108, there is disclosed the formation of various block copolymers. However, the block copolymers disclosed in U.S. Pat. No. 3,838,108, generally had to be made in one continuous process since the anionically polymerized polymer with isocyanate or polyisocyanate end caps tended to be unstable and could not be stored for any appreciable period of time. That is, moisture or active hydrogen-containing impurities would react with the highly reactive isocyanate and prevent the formation of the desired block copolymer. Moreover, in the absence of active hydrogen compounds, trimerization or dimerization of the isocyanate or isothiocyanate may occur. The reqiurement of a continuous polymerization is at times uneconomical and impractical, especially when tailor-made products are desired. Moreover, another disadvantage of the continous formation of the block copolymer is that due to various parameters involved, the precise percentage of a polyolefin-type polymer end capped by an isothiocyanate or isocyanate would vary from time to time and generally was very difficult to control or to determine immediately. Such variation tended to produce block copolymers of less than optimum and sometimes undesirable properties in situations wherein a precise stoichiometric amount of monomer or polymer was required as in the formation of a polyimide block copolymer.
Moreover, many patents have disclosed the combination of phenolic resins with rubber stocks for use as tire cord dips and/or adhesives. These patents generally depend upon the reaction of the phenolic hydroxyl for joining the two materials, for example, British Pat. Nos. 1,137,046 and 1,131,549, or use phenolic compounds which contain polymeric or oligomeric substituents, for example, Netherlands Patent No. 6,612,301. Moreover, unusual or exotic-type catalysts are required such as a metallic cocatalyst as in British Pat. No. 1,137,046 or BF.sub.3 as in Netherlands Pat. No. 6,612,301. The present invention does not require any catalyst or precautions beyond that known to the preparation of phenolic resins. Rather, the present invention generally relates to the preparation of block copolymers which are capable of being cured to give thermosetting resins which can be used as adhesives and, when mineral filled and compounded, show good flexural strength (greater than 11,000 psi) and good flexural modulus (greater than 990,000 psi), coupled with high heat distortion (230.degree. C. at 264 psi). The graft copolymers are prepared by reacting phenol-aldehyde materials with amine terminated polymers to form the graft copolymer.
U.S. Pat. No. 3,331,730 relates to the preparation of phenolic resins esterfied with unsaturated monocarboxylic acids and laminates therefrom. Once again, a polymer is prepared through reaction of the phenolic hydroxyl groups and results in a completely different polymer.